The invention relates to a medical appliance, and particularly to a medical appliance for applying pressure to a part of a human body for the purpose of stimulating blood circulation.
Such medical appliances are known which comprise a double-walled sheath adapted to fit over a limb, for example an arm or a lower leg portion, to be treated, and a pump apparatus arranged to inflate and deflate the sheath cyclically thereby to apply a pumping action to the limb and thus assist venous blood-flow therein.
A particular disadvantage of such known appliances is that they cannot be used when the limb to be treated is also to be encased in a plaster cast, or sometimes when the limb has been subjected to surgery; neither is it possible, with any appliance which completely encloses the extremity, for the physician to use the pin-prick test for nerve response at the involved extremity, nor can he carry out the essential tests to assess the state of circulation at the extremity.
A further disadvantage of known appliances is that they are not suited to continuous use by the patient.
These disadvantages are particularly significant in relation to appliances for use on feet and legs where as is known stimulation of blood flow is desirable when the limb cannot be used for walking.
We have discovered a venous pump mechanism in the sole of the human foot, which under normal walking conditions for the foot, serves to return blood from the leg into the abdomen with no assistance from muscular action.